Apparatus for continuously separating solids of explosive from liquid



L. E. WALKUP 2,490,108 APPARATUS FOR CONTINUOUSLY SEPARATING SOLIDS 0FEXPLOSIVE-FROM LIQUID Filed March 24, 1942 INVENTQR Lewis E.Wa.Ikup

ATTORNEY Patented Dec. 6, 1949 -'APBARATUS FQR'CGNTINUQUSLY SEPARAT-IN-G; SOLIDS 'OFEXPLOSIVEFROM LIQUID Wood R e .11.- es i nori to Q 3 ndutri s. n a, cqrporatie o D l Application March .24, 1942, sefia1 No;435,003 scam hm-Tee This invention .relatesqto the manufacture ofexplosives and in partic llflrto ,the separation of explosive particles,from a slurry.

, In the manufacture of explosives, in accordance with, some processes,.:smallparticles of the solid explosive are in contacts with or suspendedin lar to1u s, .,l.-id a mu t b se te therefrom before they can befurther treated or .used.

=,Simple,decantation methods, are operative for th purpo o ywithiex lqsreslhavi g a t n .ency to completely settle out, of their liquid slurriand they. er in-additie -th d sa nt g of requiring appreciableperiodsoftime for such settling out and-ofier difiiculty in; obtaining a completeseparatio oi. h w iq id ro t e plosive.

Continuous vacuum type ,filters such ;as the rotary filter, and batchtypeseparators;,such as the intermittently.operated,eentrifugabseparators, have been employed kfoiysuch,purpeses,-. but methods employing such filters areattended with seriousdisadvantages in the: manufacture, of; expl s ve eh ftame e whic ma cabme t o e high cost of operation, low production capacity, and in thecasepf the continuous vacuum type filter, difficulty incontroldue to thecritical proportions oi slurry-necessary for satisfactory fumetioning.

It is an object ofgthis invention to provide a p c for ea ytsecurine.efieeti e. s paration of particlesof -.e ;xp1osiye from a liquid.

Another obj ect ot, the invention ;.is :to -;provide es and unee pleeted e rif e ap a a u for continuously separating the components-pf aslurry composed ,of. -particles of, =explosive ;;in a liquid.

Still another object. of this;inventionis -;to -provide an economical--method ;and;-means fpn =the continuous separation of- :particles ofexplosive from an associated liquidyvhile; ailjording-opportunity for furthertreatrnent with a treating liquid during the separationprocess.

A still further object of the inventioniis taprovide an economicalmethod for-continuously treating particles of.explosivewith-a-liquid fora very short period of-time, andthereafter separating the particles ofexplosive from the. liquid.

Other objects. will \be apparent from ;=.the acoompanying descriptionand drawings, of which Fig. 1 is a verticalsection of acentrifugallseparator embodying thisinvention, and

Fig. 2 is a vertical sectionoi therotarylcontamer illustratin tecformiakemby,thee sive, and

,F fig 3 1s, a ,vertical sectionof a modified centrifugal separatorembodying the invention.

In accordance with the present inventionthe above stated objects are,accomplished by con- ,tinuously feeding; a slurry of the explosiveparticles into a rapidly rotating-container having substantiallycylindrical perforated side walls, providing/means for continuouslycollecting and dischargingtheliquid passingthrough the perfo ratior s,ar1d providing means for continuously ,cpllecting and discharging thesubstantially liquid-free explosive propelled from the mouth of thecontainer. When an intermediate treatment with a liquid is desired,means are provided for spraying wash waterorother liquid toward .theinner surface ofthe-side walls of the container during the process.

, It hasnow been found thatifa-slurry of explosive particles is fedcontinuously into arapidly rotating container having substantiallyeylindrical rperforated sidewalls, ,the explosive, as it loses itsslurry Jiquid through the perforations, first forms a; lining having,aconoidal surface in the container and then subsequently f ed, particles:e r h. a o e th ssurfa e an .are pr e e ward-1y from the- -mou thof thepontainerover t fed e 0 t e 1 1 e- ,1, e ini :a i-e ple esbe n oun o s ves-e :ide efil be .f t s u et ini xp s ve; rti isme zit en th rfora n inthepontainer walls and preventing larger parti s em elesshe.;.th ;her eeh 9 Fu the it. heslee n un h lt exp o iv may be washed or otherwisetreated-with aliquid byish e i t we i-We s r o h r li ehlt linin ex sivarticular y,ent eu per. p r tie the eo durin the s pa atin o rati Thhe-aeer ihe o; t s-i eh e th sl of explosive can be continuously fedinto the-rotati e ehtei-herge.. 'qu e nteh th he v e ih t oug ;v the-p orat o s.be ver e t .the se er. e e ewh e sw e ir rhi th na iel sef subst n i lqu e .e e eer n nu us y pr el fro em e hlofi th eehte n ehd l n be. e ee and eeht znheus conveyed away for furthertreatment-or use.

,;-.A1;n0 vel, centrifuge developed-for carrying out th pr e p t sinvent o ,i 11 sh'e 1. i Eigures 1 2 and 3, in which apontainer 13havthe ti n r re bette 1-. a e ih rie perforate side walls 3 is mountedfor rotation about-thelongitudinal axis on a rotary shaft l. A housingdismounted about, the periorate por tion ,3 of the container [3 and isadapted tQ-collect the liquid passing through the perforations and todischarge same through the outlet 6. The annular receptacle 4 with wallsI and discharge outlets 9 is mounted about the mouth of the container I3and-is adapted to collect and discharge particles of explosive propelledfrom the mouth of the container l3. A feed pipe 8 is provided to injectthe slurry of explosive into and near the bottom 2 of the container l3.Liquid inlet pipe I4 is provided to spray wash water or other liquidtoward the side walls 3 of the container l3.

In Fig. 2, the line IE] illustrates the conoidal surface of the liningof the explosive in the container l3, and application of a treatingliquid to the explosive is shown at H.

In Fig. 3, a variation in the container I3 is illustrated in which aseries of large perforations l2 are located at the mouth of thecontainer 13 and above the perforate side walls 3. The perforations i2are designed to permit passage of the substantially liquid-freeexplosive into the annular receptacle 4.

The housing 5 may be subdivided into one or more receptacles l5, I6, I?and 18 with discharge outlets 6, I9, 20 and 2!, for the purpose ofseparating the slurry liquid from the wash water, or other treatingliquids, expelled from the side walls 3 of the container.

By way of illustration, following is a description of the use of theprocess and apparatus of this invention on substantially sphericalparticles of smokeless powder prepared for instance according to theprocess described in U. S. Letters Patent 2,027,114, wherein a powderbase is suspended in water in the presence of a solvent for the powderbase and after agitation and heating to remove the solvent, smallspherical gelatinized grains of smokeless powder suspended in waterresult.

In separating such powder from its slurry liquid, a rotary container l3about seven inches in diameter and six inches high was employed. Theside walls 3 of the container were perforated with one quarter inchholes, all but the top annular row of holes l2 near the mouth of thecontainer being covered with fine mesh Dutch-weave screen. A slurrycontaining about 50% by weight of powder was fed into the container nearthe bottom and a lining of powder having a conoidal surface wasimmediately built up in the container, the surface of the lining havingan angle of about 25 to the sidewalls. Immediately after formation ofthe lining, substantially liquid-free powder was propelled from thecontainer through the annular row of perforations l2 about the mouth ofthe container. At the same time the powder slurry was being fed into thecontainer, wash water was sprayed from inlet I 4 onto about the upperhalf of the powder lining. In this way the powder, which lost its slurryliquid relatively near the bottom 2 of the container, was washedsubstantially free of any residual slurry liquid constituents whiletraveling up the surface of the lining through the spray of wash waterto the perforations l2. Washing in this manner was found to be veryefiicient requiring only a small portion of water per unit weight ofpowder.

The liquid passing through the perforations, which included both theslurry liquid and the wash water, was diverted to a storage vessel forrecovery of the treating reagents contained therein.

The powder propelled through the annular row of perforations l2 at themouth of the container was substantially free of all but the occluded '4liquid and had an average moisture content of only about 9.5%. Thecontainer was rotated at the relatively low speed of about 800-900revolutions per minute and even at this low speed the capacity was foundto be about 35,000 pounds of liquid-free powder per 24 hours. Theproduction capacity could be considerably increased by raising the speedof rotation. The continuous centrifugal separator required a muchsmaller space and only a fraction of a horsepower for operation whereasa vacuum type rotary filter having much lower production capacity wasfound to require about 22 horsepower. The effectiveness of this processis demonstrated by the fact that the 9.5% residual moisture content isthe same as that obtained by centrifuging a lot of the same powder in abatch centrifuge for 4% minutes at 1900 R. P. M.

Although in the above specific example, the process and apparatus ofthis invention are described for use on spherical gelatinized grains ofsmokeless powder it should be understood that the invention may also beemployed with other explosive materials such as bulk smokeless powders,for instance made according to the process described in U. S. LettersPatent 2,235,298, tetryl and other explosive particles, particularly ofsubstantially spherical or oval shape or agglomerates of roughlyspherical configuration.

The process and apparatus of this invention may likewise be employed tocontinuously treat even substantially dry particles of explosive withone or more liquids for relatively short periods of time, in which casethe particles of explosive may be fed, for instance through feed pipe 8,into the container simultaneously with the treating liquid, which may befed through one or more inlets [4, while the treated and substantiallyliquid-free explosive is continuously propelled from the mouth of thecontainer.

As shown in Figure 3, the process and apparatus may be readily adaptedfor maintaining a separation of the slurry liquid from the wash water orother treating liquid, which is of decided advantage in some instancesfor recovery or other purposes.

A distinct advantage in having the explosive material form the lining inthe rotary container is that depending on its angle of repose eachexplosive forms its own slope at just the angle necessary to permit theparticles to climb to the mouth of the container and an ideal filter bedfor separating the explosive slurry is thereby provided. Furtheradvantages as described above are increased economy of operation andincreased production capacity.

Since many variations may be made in the specific embodiments describedtherein without departing from the spirit and scope of the invention, itshould be understood that the invention is not limited to the detailsthereof except as set forth in the appended claims.

Having now described the invention, what is claimed as new and isdesired to be covered by Letters Patent is:

1. Apparatus for continuously separating grains of explosive from anassociated liquid, comprising the combination of a container having animperforate bottom and substantially cylindrical perforate side wallswith a conoidal-surfaced lining of said grains and mounted for rotationabout its longitudinal axis, a housing mounted about said container andadapted to continuously collect and discharge liquid passing through thelining and perforate side walls of said container, an

annular receptacle mounted about the mouth of said container andadaptedto continuously collect and discharge the substantially liquid-freegrains of explosive propelled from the mouth of said container, andmeans for rotating said container.

2. Apparatus for continuously separating smokeless powder grains from aslurry thereof, comprising the combination of a container havingsubstantially cylindrical perforated side walls with a conoidal-surfacedlining of said grains and mounted for rotation about its longitudinalaxis, a housing mounted about said container adapted to continuouslycollect and discharge liquid expelled through the lining andperforations in said container, an annular receptacle mounted about themouth of said container and adapted to collect and discharge the grainsof explosive propelled from the mouth of said container, means forforcing a liquid toward the inner perforate surface of said containerand means for rotating said container.

3. Apparatus for continuously separating grains of explosive from aslurry thereof, comprising the combination of a container havingsubstantially cylindrical perforated side walls with a conoidal-surfacedlining of said grains and mounted for rotation about its longitudinalaxis, a housing mounted about said container and provided with aplurality of compartments adapted to collect and separately dischargeliquids expelled through the lining and perforated side walls of saidcontainer at different elevations, an annular receptacle mounted aboutthe mouth of said container and adapted to collect and discharge thegrains of explosive propelled from the mouth of said container, meansfor forcing liquid toward the inner perforate surface of said container,and means for rotating said container.

4. Apparatus for continuously separating grains of explosive from anassociated liquid, comprising the combination of a container having animperforate bottom and substantially cylindrical perforate side wallswith a conoidal-surfaced lining of said grains and mounted for rotationabout its longitudinal axis, a housing mounted about said container andadapted to continuously collect and discharge liquid ejected through thelining and perforations in said container, an annular receptacle havingan outlet in its bottom mounted about the mouth of said container forcontinuously collecting and. discharging the grains of explosivepropelled from the mouth of said container, and means for rotating saidcontainer.

5. Apparatus for continuously separating grains of explosive from anassociated liquid, comprising the combination of a container having animperi'orate bottom and substantially cylindrical perforate side wallsand mounted for rotation about its longitudinal axis, a porous lining ofgranular material in said container presenting a conoidal surface havinga slope substantially equal to the angle of repose of the said grains ofexplosive, a housing mounted about said container and'adapted tocontinuously collect and discharge liquid ejected through the lining andperforations iii-said container, a receptacle having an outlet in itsbottom mounted about the mouth of said container for continuouslycollecting and discharging the grains of explosive propelled from themouth of said container, and means for rotating said container.

LEWIS E. WALKUP.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 328,190 Cloudman Oct. 13, 1885541,573 Selwig June 25, 1895 710,607 Peterson Oct. 7, 1902 781,926 WileyFeb. 7, 1905 931,749 Gentieu Aug. 24, 1909 1,545,832 Hofibauer July 14,1925 1,963,712 Moore June 19, 1934 2,119,644 Miller June 7, 19382,292,469 Olsen Aug. 11, 1942 v FOREIGN PATENTS Number Country Date1,812 Great Britain A. D. 1877 1,007,787 Germany Jan. 4, 1899 OTHERREFERENCES Weaver, "Military Explosives" (N. Y., 1917), an ed.', p. 125.

